Hayden Parker and Ben Nowell ignited a dominant display from the backline for Taieri to record a convincing victory at Bathgate Park.
With Southern enjoying a wealth of possession, it was the inspirational defence from Nowell in midfield that halted the threat from Southern.
Tactical kicking from Parker at the turnover was enough to break the spirit of the Southern pack, as he hoofed the ball downfield to put the pressure back on the Magpies.
The Taieri forward pack enjoyed a slight advantage at the set piece, but at times was exposed a little in general play, with Southern's ability to turn the ball over.
Taieri lock Kurt Webster dominated both in the set piece and in broken play, scoring two tries. Hooker Will Hurst, who also scored, had a strong presence on the field.
Although Taieri will be pleased with the victory, the scoreline could have been greater, had support players not over-run the ball.
Southern was reduced to 14 men for the final 33 minutes when captain Sam Gavigan was sent off.
Despite being a man down, Southern enjoyed a wealth of possession during the final quarter, and only committed defence stopped it from scoring more than the tries to Bryce Hosie and TJ Ioane.
Taieri 36 (Kurt Webster 2, Kori Rupene, Will Hurst, Michael Collins, Shannon Young; Hayden Parker 3 con), Southern 20 (Bryce Hosie, TJ Ioane tries; Pen Patston 2 pen, Bryce Hosie 2 con). Halftime: Taieri 19-6.
